Manually controlled linkage



Feb. 18, 1958 1.13. BUCKMAN ET AL 2,823,549

MANUALLY CONTROLLED LINKAGE Filed April 25, 1955 lo N f \70 s f /oz /i;- Fr TH 4 IN V EN TORS United States Patent MANUALLY CoNTRoLLED LINKAGE John B. Buckman and Robert D. Uthot, St. Louis, Mo., assignors to Knapp-Monarch Company, St. Louis, Mo., a corporation of Delaware Application April 25, 1955, Serial No. 503,749

4 Claims. (Cl. 74-110) This invention relates generally to a speed control device, and more particularly to a linkage arrangement wherein manual movement of a control knob effects regul-ation of the speed of an electric motor.

It is a primary object of this invention to provide a speed control device wherein straight-line motion of a sliding control knob effects positioning of a pair of electrical switch contacts relative to a motor speed responsive governor, whereby the predetermined motor speed at which the governor will effect opening and closing of the contacts may be adjusted.

It is another object to provide a novel linkage arrangement for translating the relatively long linear movement of a manual control knob into relatively short linear adjustment of a pair of governor-actuated contacts, whereby variable speed control of a motor at full power may be effected simply and accurately.

It is a further object to provide a novel linkage arrangement utilizing a plurality of pivoted levers for transmitting the linear movement of a manual control to the linear movement of an adjusting means.

With these and other objects in view, our invention consists in the construction, arrangement and combina- Vtion of the various parts of our Speed Control Device whereby the objects contemplated are obtained as hereinafter more fully set forth, pointed out in our claims and illustrated in the accompanying drawing, wherein:

Figure 1 is a fragmentary top plan view of the power unit construction of a mixer embodying the speed control device of the present invention, parts being broken away and in section to show details of construction;

Figure 2 is a side elevational view in vertical crosssection through the housing enclosure of Figure 1;

Figure 3 is a vertical cross-sectional view taken substantially as indicated on the line 3 3 of Figure 2; and

Figure 4 is a detailed view looking in the direction 4--4 of Figure 3, showing the operation of the lower control bracket.

Referring now to the drawing, we have indicated at a housing enclosure for a power unit construction of the type employed in a mixer or the like. As best seen in Figure 2, the housing 10 encloses an electric motor, indicated generally at 12. The motor 12 rotatably drives a power shaft 14, which is adapted to be connected by means of suitable gearing in the well-known manner to a pair of mixer beaters or the like. The housing 10 includes a top wall 16, a pair of side walls 17 and 18, and a forward end wall 19.

The forward end of the power shaft 14 is supported by bearings provided by a bracket assembly 20. The bracket assembly 20 is ixedly secured to the walls of the housing 10 by means of suitable resilient mounts, not shown.

A governor unit, indicated generally at 22, is positioned at the forward terminal end of the power shaft 14 within the forward end wall portions of the housing 10. The governor 22 includes a hub 24 which is integrally secured to the power shaft 14 closely adjacent its forward terminal end. A spider 26 is secured to the hub 24, and

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comprises a rotatable arm construction connected by weighted rivets 28 to a second and similar spider 30. The second spider 30 terminates in a second hub 32 which is axially aligned with and spaced from the first hub 24. The second hub 32 carries an insulated button 34 at its forward face.

The insulated button 34 is arranged to cooperatively contact an insulated nib 36 which is carried by a governor contact blade 38. A second governor contact blade 40 is positioned closely adjacent the rst blade 38. The lblades 38 and 40 are carried by a contact supporting arm 42, and are normally spaced from each other so as to closely position a pair of open contacts 43. As will hereinafter be made more apparent, movement of the contact blade 38 to the right as seen in Figure 2, will cause the contacts 43 to be closed.

An adjusting pin 44 is supportingly positioned for leftto-right reciprocation within the housing 10. The pin 44 is carried by a supporting strap 46 having depending apertured arms 48 through which the pin 44 is slidably received. The pin 44 is formed with flattened sides, as best seen in Figure 3, and the apertures in the arms 48 through which the pin 44 extends are similarly formed so as to preclude rotation of the pin 44. A screw 50 lixedly secures the strap 46 to a gear housing, indicated generally at 52. The gear housing 52 is carried by the bracket assembly 20 in xed position within the housing 10, and receives the power shaft 14 therethrough. The housing 52 includes outwardly extending portions 54 and 56 from which beater drive shaft housings 58 and 60 depend in a downward direction. A pair of beater drive shafts 62 and 64 extend downwardly from the housings 58 and 60, and are adapted to receive and operatively drive a pair of beater shafts. The housing 52 encloses conventional gearing (not shown) for the purpose of transmitting driving rotation of the power shaft 14 to the power drive shafts 62 and 64 in the well known manner.

Upper and lower control brackets 66 and 68 are positioned above and below the power shaft 14. The brackets 66 and 68 comprise a pair of spaced horizontal arms 70, 71 and 72, 73, respectively. The horizontal bracket arms are disposed in superposed relation, one above the other, and are interconnected by inclined intermediate portions 74 and 75, respectively (see Figure 3). A vertical pivot pin 76 extends through the outwardly extending portion 54 of the gear housing 52, and is rotatable therein. The horizontal arms 71 and 72 of the upper and lower brackets 66 and 68, respectively, are rigidly secured to the pivot pin 76 at its opposite ends above and below the housing portion 54. In this manner, rotation of the upper bracket 66 effects rotation of the pivot pin 76, which is in turn transmitted to the lower bracket 68 to effect similar rotation thereof.

A set screw 78 is screw-threadedly received within a collar 80 through which the adjusting pin 44 extends. In this manner, the set screw may be tightened so as to effect a positive connection to the pin 44. The terminal end of the lower horizontal arm 73 of the lower bracket 68 is forked, as best seen in Figure 4, to engage the set screw 78 while permitting some degree of free motion.

A sleeve 82 is positioned in surrounding relation about t-he pin 44 adjacent its forward end. The forward terminal end of the pin 44 is screw-threaded, as indicated at 84. A locking nut 86 cooperates with the screwthreaded end 84 of the adjusting pin 44 to lixedly secure the support arm 42 to the pin 44 in contacting engagement against one end of the sleeve 82. The other end of the sleeve 82 is formed with an enlarged flange portion providing an abutment for one end of a loading spring 88. .The loading spring 88 abuts at its other end against a depending arm 48 of the supporting strap 46. The spring 88 is biased in compression so as to position the sleeve 82, contact supporting arm 42, and lock-ing nut 86 in tight contacting engagement, as best seen in Figure 2.

An elongated straight-line slot 90 is formed in the upper wall 16 of the housing 10, and extends in a lengthwise direction. A control lever 92 is positioned within the Vhousing directly below the slot 90. The lever 92 is formed with an arcuately curved slot 94, extending in generally the saine longitudinal direction as the housing slot 90. The lever 92 is pivotally connected to the top wall 16 of the housing at 96. A control knob 98 is positioned atop the housing 10, and screw-threadedly receives a screw 100 which extends downwardly therefrom through the slot 90. The screw 100 also extends downwardly through the arcuate slot 94 of the lever 92, and carries a resilient stop means 106 at its lowermost end directly below the head portion thereof. The stop means 106 comprises a U-shaped spring element which serves to exert a force tending to seat the knob 98 against the lever 92, thereby providing a sliding guide for move- `ment of the screw 100 along the curved slot 94 and effecting xed positioning of the knob 98 in any position of sliding adjustment regardless of motor vibration.

A lever pin 102 is fxedly riveted to the control lever 92 and extends downwardly therefrom through an arcuate slot 104 in the horizontal bracket arm 70 of the upper bracket 66.

In the operation of the present invention, straightline motion of the sliding control knob 98 along the straight-line slot 90 of the top wall 16 of the housing 10 will be translated to effect horizontal positioning of the governor Contact blades 38 and 40 relative to the governor hub 32 and its insulated button 34.

As shown in `the drawing, the knob 98 is disposed in its furthest right position, which is the Off control position. As the knob 98 is manually moved from right to left, as seen in the drawing, our novel linkage arrangement will effect movement of the contact blades 38 and 40 into closer adjacent relation to the rotating parts of governor 22. It will be apparent that the faster the motor drives the power yshaft 14, the faster the hubs 24 and 32, and the spiders 26 and 30, will be rotated. Due ,to centrifugal forces acting upon the weights 28, relatively fast rotation will cause the weights 28 to move outwardly and the hub 32 to move to the left toward the hub 24. Relatively slower rotation will permit the normal resilience of the'spiders 26 and 30 to space the hub 32 toward the right away from the hub 24.

When hubs 32 and 24 of the governor 22 are widely spaced, the insulated .button 34 will contact the insulated nib 36 to effect a bending of the contact blade 38 toward the contact blade .40. Such a bending of the blade 38 will etect an engagement of the contacts 43. As the motor rotates faster, the hub 32 will be withdrawn so as to permit the normal spring bias of the switch blades 38 and 40 to effect an opening separation of the contacts 43. Suitable electrical circuitry, in the conventional manner, will serve to provide current to the motor when the contacts 43 are closed, but will interrupt the supply of current to the motor when the contacts 43 are open. The governor 22 will therefore serve to alternately open and close the contacts 43 in the well known functional manner termed hunting, to effect a relatively constant motor speed. It will be obvious that the particular speed may be determined by the distance which the hub 34 must be withdrawn away from the contact blade 38 to eifect an opening of the contacts 43.

When the control knob 98 is moved from the Off position toward the left, the linkage arrangement of the present invention will operate to slide the adjusting pin 44 to the left, thereby bringing the contact blades 38 and 40 into closely adjacent relation with the governor hub 32. As the control knob 98 is moved from right to left, therefore, the motor speed will be varied Vfrom Low to Hig-h. In practice, the adjustment of parts is preferably predetermined so that the motor shaft will run at a speed of about 8000 R. P. M. when the control is positioned at the extreme Low or right hand end, and will run at a speed of about 17,500 R. P. M. when positioned at the extreme High or left hand end.

Although the arrangement of the present invention is applicable to any mixer having a governor-contact type of speed control, such as that shown and described in Holstein Patents 2,623,961 and 2,623,962, it is particu.- larly intended for use with a combined mixer-liquidizer construction such as that shown in Moore Patent 2,685,435. In constructions of the mixer-liquidizer type, both ends of the motor drive shaft are used to do work. A direct coupling at one end of the motor serves to drive liquidizer blades at motor speed, while reduction gearing at the other end of the motor drive shaft provides a ratio, say of 171/2 to l, for driving the mixer beaters at a sufliciently reduced speed. When used as a food mixer. the beater shafts of such constructions are desirably ranged in `speeds from about 460 R. P. M. at the Low end, to about 1000 R. P. M. at the High end.

Manual actuation of the `control knob 98 will Vserve to adjust the operative range of the governor 22 so as to regulate the motor speed as desired. As the control knob 98 is moved to the left, the screw 100 carried by the knob will be moved along the `straight slot in the housing top w-all 16. At the same time, the screw will also travel along the arcuately curved slot 94 of the speed control lever 92. ln this way, the lever 92 will be caused to pivot about the connection 96 so that the right hand end thereof, as viewed in Figure 1, will be moved along an arcuate path. This arcuate movement of the lever 92 will effect a movement of the lever pin 162 within the arcuate slot 104 of the upper horizontal arm 70 of bracket 66. This sliding movement of the lever pin 102 within the slot 104 will eifect a pivotal movement of the bracket 66 about the vertical axis of the pivot pin 76. Because of the rigid interconnection of the brackets 66 and 68 to the pivot pin 76, such pivotal movement of the upper bracket 66 will be transmitted to the lower bracket 68. Pivotal movement of the lower bracket 68 will effect an arcuate movement of the forked terminal end of the lower horizontal portion 73, which will be translated through the set screw '78 to the adjusting pin 44, thereby effecting horizontal reciprocation of the rod 44. Such horizontal reciprocation of the rod 44 will serve to adjustably position the contact blades 38 and 40 with respect to the rotating parts of the governor assembly 22 for effecting the operation 'heretofore described.

Changes may be made in the construction and 1arrangement of the parts of our speed control lswitch without departing from the real spirit and purpose of our invention, and it is our intention to cover by our claims any modied forms of structure or use of mechanical improvements which may be reasonably included within their scope. Y

What we claim as new and desire to obtain by Letters Patent of the United States is:

y l. ln an appliance housing of the type having an elongated linear slot, a control device comprisinga manual control knob disposed outside of the housing and having a portion extending inwardly through the housing slot, an elongated control lever pivotally mounted within the housing directly inward of the housing slot, said extending portion of the control knob extending inwardly through an elongated curved slot formed in said lever, bracket means pivotally mounted within the housing and operatively connected to said control lever, movement of said knob along the housing slot being translated through said linkage means to eiect rotation of said bracket means, and an adjusting pin mounted within the housing for reciproeation, said bracket means being operatively connected to said adjusting pin whereby rotational movement of said bracket means serves to effect reciprocation of said adjusting pin.

2. In an appliance housing of the type having an elongated linear slot, a speed control device comprising a manual control knob disposed outside of the housing and having a portion extending inwardly through the housing slot, linkage means within the housing operatively connected to said inwardly extending portion of said control knob, bracket means pivotally mounted within the housing and operatively connected to said linkage means, said bracket means providing spaced parallel arm portions, one of said bracket arms having an elongated curved slot formed therein, said linkage means providing a pin extending inwardly through said bracket arm slot, and an adjusting pin mounted within the housing for reciprocation, the other of said bracket arms being operatively connected to said adjusting pin whereby rotational movement of said -bracket means serves to effect reciprocation of said adjusting pin.

3. ln an appliance housing of the type having an elongated linear slot, a speed control device comprising a manual control knob disposed outside of the housing and having a portion extending inwardly through -the housing slot, an elongated control lever pivotally mounted within the housing directly inward of the housing slot, said extending portion of the control knob extending inwardly through an elongated curved slot formed in said lever, bracket means pivotally mounted within the housing and providing spaced parallel arm portions, one of said bracket arms being disposed directly inward of said control lever and having an elongated curved slot formed therein, a pin ixedly secured to said control lever and extending inwardly through said bracket arm slot, and an adjusting pin mounted within the housing for reciprocation, the other of said bracket arms being operatively connected to said adjusting pin, whereby movement of said control knob along the housing slot will be translated through said control lever and bracket means to eiect recprocation of said adjusting pin.

4. In an appliance housing of the type having an elongated linear slot, a control device comprising a manual control knob disposed outside of the housing and having a portion extending inwardly through the housing slot, an elongated control lever having its one end pivotally mounted within the housing directly inward and at one end of the housing slot, said extending portion of the control knob extending inwardly through an elongated curved slot formed in said lever, bracket means pivotally mounted within the housing and operatively connected to said control lever at its other end, movement of said knob along the housing slot being translated through said linkage means to eiect reduced-motion rotation of said bracket means, and an adjusting pin mounted within the housing for reciprocation, said bracket means being operatively connected to said adjusting pin whereby relatively reduced rotational movement of said bracket means in response to relatively long reciprocating movements ofsaid knob in the housing slot serves to efrect relatively short reciprocating movements of said adjusting pin.

References Cited in the file of this patent UNITED STATES PATENTS 2,488,364 Zilliotto Nov. 15, 1949 2,719,945 Tull Oct. 4, 1955 FOREIGN PATENTS 452,177 Italy Oct. 10, 1949 

